Grouping-Based Dynamic Power Management for Multi-threaded Programs in Chip-Multiprocessors

In the embedded systems field, the research focus has shifted from performance to considering both performance and power consumption. Previous research has investigated methods to forecast the processing behavior of programs and adopt dynamic voltage and frequency scaling (DVFS) technique to adjust the frequency of processor to meet the needs of various phase behavior of threads of programs. However few researches have paid attention to the overhead of DVFS. Generally, DVFS brings processor core unavailable time from 10 us to 650 us. Adjusting frequency for every thread may encounter unanticipated overhead especially for multi-threaded programs.The objective of this study is to take performance, power consumption and overhead into consideration and give a low overhead power management that adjusts the frequency of processor for every group of threads instead of every thread. The proposed approach consists of three works: phase behavior prediction, DVFS controlling and workload migration. To demonstrate the effect of our approach, we implemented these works on a real Linux system and compared our approach with the system without DVFS and the system with DVFS for every thread. The results present that our approach improves 15-40% power consumption with 2-10% performance penalty. Moreover, it can reduce 94-97.5% processor core unavailable time, more than the system with DVFS for every thread.